CSS px aren't pixels

Published on Monday, November 4, 2013

This is fascinating. Px is an angular measurement, convertible from radians.

The moon from earth is about 24.3px wide, for example. The Eiffel Tower from a mile away is about 550.5px tall. That means that when you do “{ width: 24.3px }” in CSS 2.1, you're making something as wide as the moon looks to be.

All these years of web slinging and I always thought it meant "pixels".